Institute for Advanced Study, Chengdu University, Chengdu 610100, P. R. China.
Nanoscale. 2018 Dec 20;11(1):356-364. doi: 10.1039/c8nr07692h.
Antiferromagnetic (AF) spin devices could be one of the representative components for applications of spintronics thanks to the numerous advantages such as resistance to magnetic field perturbation, stray field-free operation, and ultrahigh device operation speed. However, detecting and manipulating the spin of AF materials is still a major challenge due to the absence of a net magnetic moment and spin degeneracy in the band structure. Bipolar antiferromagnetic semiconductors are promising solutions to these problems. Herein, using density functional theory calculations, we present asymmetrical functionalized double MXenes (Cr2TiC2FCl) that behave as a novel bipolar antiferromagnetic semiconductor (BAFS) with vanishing magnetism, in which the valence band and conduction band around the Fermi level exhibit opposite spin directions. Remarkably, gate voltage can manipulate the spin orientation of the AF Cr2TiC2FCl and lead to a transition from BAFS to half-metal antiferromagnets (HMAF). Moreover, the mixed functionalized double MXenes with various F/Cl concentrations show the BAFS feature due to the different chemical environment for the Cr atom. Our results presented herein open a new strategy towards AF spintronics and the realization of the AF spin field effect transistor.
反铁磁（AF）自旋器件由于其众多优点，例如抗磁场干扰、无杂散场操作和超高的器件工作速度，有望成为自旋电子学应用的代表性组件之一。然而，由于带结构中没有净磁矩和自旋简并，检测和操纵 AF 材料的自旋仍然是一个主要挑战。双极反铁磁半导体是解决这些问题的有前途的方案。在此，我们使用密度泛函理论计算，提出了不对称官能化的双层 MXenes（Cr2TiC2FCl），其表现为一种新型的双极反铁磁半导体（BAFS），具有消失的磁性，其中费米能级附近的价带和导带表现出相反的自旋方向。值得注意的是，栅极电压可以操纵 AF Cr2TiC2FCl 的自旋方向，并导致从 BAFS 到半金属反铁磁体（HMAF）的转变。此外，具有不同 F/Cl 浓度的混合官能化双层 MXenes 由于 Cr 原子的化学环境不同，表现出 BAFS 特征。我们在此提出的结果为 AF 自旋电子学和 AF 自旋场效应晶体管的实现开辟了一条新的策略。
